Xavier NX Gpio pin numbering does not match

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

Hi all,

When looking at the following explanation: https://docs.nvidia.com/jetson/archives/l4t-archived/l4t-3271/index.html#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/adaptation_and_bringup_xavier_nx.html#wwpID0E0NL0HA
To calculate the pin number (“Hence, the GPIO number of GPIO3_PZ.07 is 320+(8*25)+7 = 527”)
However this does not match the pin numbers I am seeing on my Jetson?
When I check with cat /sys/kernel/debug/gpio I see gpio-499 (PZ.07)
Where does this difference come from?

3

hello r.vries,

please check release tag for your current release version, i.e. $ cat /etc/nv_tegra_release
assume you’re using JP-5.1.x release, it’s due to GPIO calculation range has changed.

4

Where can I find the updated GPIO calculation range? I am indeed on JP-5.1.x

5

Has the calculation actually changed or is there a bug?

6

hello r.vries,

you may looking kernel init messages for allocation ranges.
for example, $ sudo dmesg | grep "registered GPIOs"

$ sudo dmesg | grep "registered GPIOs"
[    3.054090] gpiochip0: registered GPIOs 504 to 511 on max77620-gpio
[    7.286094] gpiochip1: registered GPIOs 335 to 503 on tegra194-gpio
[    7.287796] gpiochip2: registered GPIOs 305 to 334 on tegra194-gpio-aon
8

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